#include <iostream>
#include <fstream>

using namespace std;

ifstream f("flip.in");
ofstream g("flip.out");

int n,m;
int t[17][17];
int sum;

void recalculate()
{
	sum = 0;
	for (int i = 0; i <= n; i++) t[i][0] = 0;
	for (int j = 0; j <= m; j++) t[0][j] = 0;
	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= m; j++)
		{
			t[i][0] += t[i][j];
			t[0][j] += t[i][j];
			sum += t[i][j];
		}
}

int main()
{
	f >> n >> m;
	for(int i = 1; i <= n; i++)
		for (int j = 1; j <= m; j++)
		{
			f >> t[i][j];
			t[i][0] += t[i][j];
			t[0][j] += t[i][j];
		}
	for (int i = 1; i <= n; i++)
	{
		if (t[i][0] < 0)
		{
			for (int j = 1; j <= n; j++)
				t[i][j] *= -1;
			recalculate();
		}
	}
	for (int j = 1; j <= m; j++)
	{
		if (t[0][j] < 0)
		{
			for (int i = 1; i <= n; i++)
				t[i][j] *= -1;
			recalculate();
		}
	}
	g << sum;
	f.close();
	g.close();
	return 0;
}